It has been shown that the theaรavins and thearubigin hump of decaffeinated aqueous extracts of black tea remain virtually stable for up to 850 min, thus permitting their automated overnight analysis. Within-run coefficients of variation for the total chromatogram area and peak area for each of the major theaรavins, following repeated (up to 10 times) injections of a single extract, did not exceed 2ร5 and 6ร0%, respectively. The corresponding values obtained by pooling data obtained on three separate occasions were 3ร0 and 7ร3%, respectively. Trend-line analysis indicated that there was a tendency for each of the areas studied to decline by factors in the range 0ร11ร0ร53% of the original value per injection. This factor was not statistically signiรcant for theaรavin-3,3@digallate but reached 5% signiรcance for theaรavin and total chromatogram area and 1% for both theaรavin monogallates. The magnitude of these changes is too small to warrant an avoidance of automated sample handling in routine screening or quality assurance programmes where the increased throughput allowed is advantageous. It was also noted that the use of citric acid to acidify the chromatographic solvents was not superior to acetic acid.